Gates are commonly used in fence lines or farmyards to allow access and to secure vehicles, property or livestock.
However, for a vehicle to pass through the gate the driver has to vacate the vehicle to open the gate and then return it to the closed position once the vehicle has been driven through the gate. The opening and closing of gates can thus become time consuming.
Conventional gate opening mechanisms make use of electric motors in order to drive the opening and closing of the gate. Such mechanisms consume power and require connection to a power source upon installation, which can be problematic when the gate is to be installed a distance from the nearest premises or power lines. In addition, conventional powered gate mechanisms resist manual operation and thus inhibit use by pedestrians.
Some gate opening devices are known that utilise fluid power for opening and closing gates, the fluid being compressed by a vehicle driving over an actuator as it approaches a gate, the compressed fluid then opening a gate, and vice versa as the vehicle drives away from the gate. Although this goes some way to solving the problem if electrically powered gates problems arise when the gate borders directly a public road it is not usually possible to position the actuator in the public road. A further type of device is disclosed in the applicants prior PCT publication WO 2007/119062 which discloses a mechanical device that uses gravity to close the gate.
The present invention seeks to provide an improved mechanism for opening and closing a barrier.